D23208: Use CMake find_dependency in CMake config file instead of find_package

[Christophe Giboudeaux]

cgiboudeaux accepted this revision.

REVISION DETAIL
  https://phabricator.kde.org/D23208

To: daandemeyer, #framework_syntax_highlighting, dhaumann, cgiboudeaux
Cc: cgiboudeaux, kwrite-devel, kde-frameworks-devel, LeGast00n, gennad, 
bmortimer, domson, michaelh, genethomas, ngraham, bruns, demsking, cullmann, 
vkrause, sars, dhaumann